1. Field of the Invention
This automatic insertion device may be used to sense the pressure inside of a fluid pipeline or to remove liquids therefrom. The preferred embodiment may be used to insert various types of sensors or measuring devices into a pipeline, e.g. a turbine meter, a temperature sensor, a pitot probe, or a doppler flow measuring device. Another embodiment may be used for insertion of a pumping device sometimes referred to as a sampler.
2. Description of the Prior Art
U.S. Pat. No. 4,177,676 which issued on Dec. 11, 1979, discloses a "Sensor Positioning Apparatus" which was invented by Robert H. Welker. The apparatus disclosed in the '676 patent uses a double acting cylinder and was designed to be permanently installed on a pipeline. Welker Engineering Company has sold various devices which embody the concepts disclosed in the '676 patent; however, the overall length of the apparatus in contrast with overhead clearance sometimes limits its use.
After a pipeline has been constructed, it will sometimes be necessary to install a sensor or other device at some remote location. Because the pipeline is typically located underground, a pit must be dug in order to gain access to the pipeline. The typical pit will be fitted with doors which close over the pit protecting it from rain and snow. The doors also prevent cattle, people, snakes and other creatures from falling into the pit. In most situations, the apparatus described in the '676 patent, when mounted on the pipeline in a pit, has prevented closure of the pit doors. Because of the double acting cylinder, it was impossible to shorten the overall height of the apparatus. In these situations, the pits fill with water and/or snow which makes maintenance difficult, if not impossible.
U.S. Pat. No. 4,387,592, which issued on June 14, 1983, discloses a "Probe Insertion Apparatus" which was invented by Robert H. Welker. Welker Engineering Company has sold various devices which embody the concepts disclosed in the '592 patent. The apparatus disclosed in the '592 patent relies upon a single acting cylinder connected by means of a yoke to an elongated probe body. The apparatus can be disassembled after the probe body has been inserted into a pressurized pipeline; however, the configuration is also limited by clearance. If the single acting cylinder is not removed, the apparatus shown in the '592 patent has the same height disadvantages as the apparatus disclosed in the '676 patent.
U.S. Pat. No. 4,346,611 which issued on Aug. 31, 1982, discloses an "Insertion Regulator for Pressurized Pipelines" which was invented by Robert H. Welker. The '611 patent discloses an apparatus to be permanently connected to a pipeline for inserting and removing a regulator therein.
All of the aforementioned inventions disclose an apparatus which is rather lengthy and therefore limited in use. In pit applications, the height of these devices frequently prevents closure of the pit doors, allowing the pit to fill with rainwater and/or snow. These space limitations cannot be overcome because the depth of the subsurface pipeline is not subject to alteration. Leaving pit doors open is not wise because reptiles and other noxious creatures frequently find their way into the pits if the doors are not securely closed which makes maintanance and service of these devices most unpleasant.
In aboveground installations, the aforementioned devices are typically enclosed in a sheet metal building or shed. In some installations, it will be necessary to cut a hole in the top or side of the shed to accommodate these devices or build a larger shed at increased cost. In other aboveground installations, there may be a series of parallel pipelines spaced three to four feet apart. If a horizontal installation is required in a parallel piping situation, many of the aforementioned devices cannot be used because of their overall length. Again, the spacing of the piping is not subject to easy or economical alteration.
The present invention is approximately 40% shorter in overall length than the aforementioned prior art devices when measured before insertion of the turbine or other sensor into the pipeline. This reduction in overall length allows the placement of insertion devices in many parallel piping situations which were not heretofore accessible by prior art devices. For example, a prior art device for insertion in a 24 inch pipeline would be approximately 82 inches in overall length; the present invention for insertion in a 24 inch pipeline would typically be 47 inches in overall length prior to insertion and removal of the cylinder.
In some situations, a doppler measuring device will be applied to a pipeline for measuring flow. Some doppler flow measuring devices require a horizontal installation with a transmitter on one side of the pipeline and a receiver on the opposite side of the pipeline. In some applications, both the transmitter and receiver are mounted on one insertion device; in other applications, the transmitter and receiver can utilize separate automatic insertion devices. If it is necessary to dig a pit to accommodate subsurface installation of two automatic insertion devices on a horizontal mode, any reduction in overall length of the automatic insertion device is an advantage because it reduces the size of the pit.
A group of other patents owned by Northern Natural Gas Company and/or Internorth, Inc. disclose various siphon devices including U.S. Pat. Nos. 4,155,376, issued on May 22, 1979; 4,282,894, issued on Aug. 11, 1981; and 3,345,616 issued on Aug. 24, 1982. All of these siphon patents disclose an apparatus which is long, ungainly and cumbersome.
The present invention discloses a compact apparatus which overcomes many of the disadvantages and problems associated with prior art devices.
The current invention, with slight modification, can be used for a multitude of applications, making it an extremely attractive product from the manufacturer's point of view. The current invention can be used as a pressure sensor or to withdraw fluids from a pipeline; in one version, it can be used for the insertion of a temperature sensor, a pitot probe, a turbine meter, or a doppler measuring device. An alternate embodiment allows insertion and withdrawal of a pump or sampling device into and from a pipeline.
High pressure pumps have been disclosed in U.S. Pat. No. 3,945,770 by Robert H. Welker. Improvements in this apparatus are further disclosed in U.S. Pat. No. 4,403,518 and pending application Ser. No. 06/456,328 and Ser. No. 06/222,362, also by Robert H. Welker. These pumps have been used to place odorants and hydrate inhibitors in natural gas pipelines; they have also been used in cryogenic service to pump liquid carbon dioxide. They have been used in other applications to pump various fluids such as water. These pumps have been integrated with sample vessels as disclosed in patent application Ser. No. 06/654,937 by Brian H. Welker. In U.S. Pat. No. 4,440,032, a sampler incorporating a purge system is disclosed. Vacuum breakers for use in high pressure pumps are disclosed in U.S. Pat. No. 4,470,773.